The great and wise Oatmeal has answered my inquiry, and given his blessing to the design.
Here is the revised copy, pending submissions:

Piggers: the ‘default’ sports team in The Oatmeal. To the best of my knowledge, they had no logo/mascot.
Now they do, and any subsequent version or offering will clearly be a poor and inferior imitation of specious origin (even if it happens to be crafted by the owner of said intellectual property).
Now having so strategically placed myself upon my petard, I shall endeavor to contact the Oatmeal, and grovel shamelessly for his persimmons to submit the design to a t-shirt company so that I can make profit from his work.